// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_TRACING_POWER_TRACING_AGENT_H_
#define CONTENT_BROWSER_TRACING_POWER_TRACING_AGENT_H_

#include <memory>

#include "base/macros.h"
#include "base/memory/ref_counted_memory.h"
#include "base/threading/thread.h"
#include "base/trace_event/tracing_agent.h"
#include "content/public/browser/browser_thread.h"
#include "tools/battor_agent/battor_agent.h"
#include "tools/battor_agent/battor_error.h"

namespace base {
template <typename Type>
struct DefaultSingletonTraits;
} // namespace base

namespace content {

class PowerTracingAgent : public base::trace_event::TracingAgent,
                          public battor::BattOrAgent::Listener {
public:
    // Retrieve the singleton instance.
    static PowerTracingAgent* GetInstance();

    void StartAgentTracing(const base::trace_event::TraceConfig& trace_config,
        const StartAgentTracingCallback& callback) override;
    void StopAgentTracing(const StopAgentTracingCallback& callback) override;
    void RecordClockSyncMarker(
        const std::string& sync_id,
        const RecordClockSyncMarkerCallback& callback) override;

    bool SupportsExplicitClockSync() override;

    // base::trace_event::TracingAgent implementation.
    std::string GetTracingAgentName() override;
    std::string GetTraceEventLabel() override;

    // BattOrAgent::Listener implementation.
    void OnStartTracingComplete(battor::BattOrError error) override;
    void OnStopTracingComplete(const std::string& trace,
        battor::BattOrError error) override;
    void OnRecordClockSyncMarkerComplete(battor::BattOrError error) override;
    void OnGetFirmwareGitHashComplete(const std::string& version,
        battor::BattOrError error) override;

private:
    // This allows constructor and destructor to be private and usable only
    // by the Singleton class.
    friend struct base::DefaultSingletonTraits<PowerTracingAgent>;

    PowerTracingAgent();
    ~PowerTracingAgent() override;

    void FindBattOrOnFileThread(const StartAgentTracingCallback& callback);
    void StartAgentTracingOnIOThread(const std::string& path,
        const StartAgentTracingCallback& callback);
    void StopAgentTracingOnIOThread(const StopAgentTracingCallback& callback);
    void RecordClockSyncMarkerOnIOThread(
        const std::string& sync_id,
        const RecordClockSyncMarkerCallback& callback);

    // Returns the path of a BattOr (e.g. /dev/ttyUSB0), or an empty string if
    // none are found.
    std::string GetBattOrPath();

    // All interactions with the BattOrAgent (after construction) must happen on
    // the IO thread.
    std::unique_ptr<battor::BattOrAgent, BrowserThread::DeleteOnIOThread>
        battor_agent_;

    StartAgentTracingCallback start_tracing_callback_;
    StopAgentTracingCallback stop_tracing_callback_;
    std::string record_clock_sync_marker_sync_id_;
    base::TimeTicks record_clock_sync_marker_start_time_;
    RecordClockSyncMarkerCallback record_clock_sync_marker_callback_;

    DISALLOW_COPY_AND_ASSIGN(PowerTracingAgent);
};

} // namespace content

#endif // CONTENT_BROWSER_TRACING_POWER_TRACING_AGENT_H_
